Concrete vibrators



Feb. 22, 1966 a. G. EISENBEIS 3,236,502

CONCRETE'VIBRATORS Filed Aug. 10. 1961 2 Sheets-Sheet l l ll GEORGE 6. E ISE NEE IS ATTO Y Feb. 22, 1966 e. G. EISENBEIS CONCRETE VIBRATORS 2 Sheets-Sheet 2 Filed Aug. 10, 1961 lllliMlIIIl W W 4 m .8. r mmofiiwf w //\||1|\ Ewin m. 3% 956m n g 6 ESfiEm U Q b SQ: Q A/H\ mmom r ::M\ Q t k 1 k k at 0 J/ m bk mmodizm INVENTOR GEORGE 6. E/SENBE/S United States Patent Ofifice 3,236,502 Patented Feb. 22, 1966 3,236,502 CONCRETE VIBRATORS George G. Eisenbeis, Conklin, N.Y., assignor to Stow Manufacturing Co., Binghamton, N.Y., a corporation of New York Filed Aug. 10, 1961, Ser. No. 130,600 7 Claims. (Cl. 259-1) This invention relates to improvements in concrete vibrators, and is more particularly addressed to an improved head design for concrete vibrators of the immersion type.

Traditionally, the heads of immersion-type concrete vibrators widely used in compacting or densifying concrete blocks, columns and the like which are set in deep forms, as distinguished from concrete slabs, floor, etc. which are set in shallow forms, have been of round section, but more recently so-called square-head vibrators have come into limited use. In an eifort to evaluate the relative merits of the squareand round-head vibrators, extensive tests were made of one against the other and these conclusively established that the square-head vibrator performs faster than the old round-head one, due apparently to the ability of the square-head vibrator to transmit energy in the form of pulses or vibrations to the concrete mass in which it is immersed more effectively than the round-head vibrator. However, because of the substantially lesser wall thickness of the square head as compared to the round-head vibrator which is more or less dictated by the economics and weight factors attaching to the new configuration, the square-head vibrator Wore out much more rapidly than did the round head. Furthermore, due to the increased power requirements of the square-head vibrator, the flexible shaft used to drive the eccentrically-weighted spindle component thereof failed after x hours of continuous operation whereas the flexible shaft driving the round-head vibrator continued to operate coolly and efliciently for many hours thereafter.

Prompted by the results of this analysis, the present invention set out and has for its major object not only to combine the better-wear and long-life properties of the conventional round-head concrete vibrator with the greater effectiveness of the vibrator having a non-round head (as exemplified by the then known square-head vibrator) in transmitting energy to a concrete mass in which the head is immersed, but also, and borrowing from the demonstrable advantages of the square-head vibrator over the older round-head vibrator, to devise, if possible, a head configuration that was better in terms of effectiveness than the said square-head vibrator.

A more particular object of the invention was to improve the eifectiveness of the conventional round-head vibrator through modification of its external configuration, thereby to preserve the long-life and high-strength characteristics of the basic round-head vibrator, as contrasted with the square-head vibrator.

The above and other objects and features of advantage of the improved concrete vibrator according to the present invention will appear from the following detailed description thereof, in which reference is made to the accompanying drawings illustrating preferred structural forms of the new head, and diagrams which graphically depict the improved advantages thereof over the known roundand square-head vibrators, in which FIG. 1 is a longitudinal quarter-section of one form of improved concrete vibrator using the basic round-head design, with modified external configuration according to the invention;

FIG. 2 is a section taken along line 2-2 of FIG. 1, which illustrates a fabricated construction of vibrator head employed in FIG. 1;

FIGS. 3, 4 and 5 are sectional views corresponding to FIG. 2, but illustrating modified configurations of the existing round-head vibrator according to the invention;

FIG. 6 is a diagrammatic view graphically depicting the action of the round-head vibrator immersed in a mass of noor substantially no-slump concrete, the view illustrating the head at the 12 ocloek position of its orbital movement within said concrete mass;

FIG. 7 is a view similar to FIG. 6, illustrating the action of the square-head vibrator operating within a concrete mass, also shown in the 12 oclock position of its orbital movement, and

FIGS. 8 and 9 are diagrammatic views illustrating respectively the action of the four-splined and six-splined round-head vibrator according to the invention in a mass of concrete in which said heads are immersed, the views similarly illustrating the heads in the 12 oclock position of their orbital movement.

Referring to the drawings, and more particularly to FIGS. 1 and 2, which respectively illustrate the constructional details and one form of new external configuration of the concrete vibrator head according to the invention, it will first be noted that except for such external configuration, the illustrated head incorporates the basic design of the well known round-head vibrator. That is to say, it comprises a non-rotary, elongated thick-wall shell or housing 10 which encloses within its bore a correspondingly elongated, eccentrically-weighted, rotatable spindle 12 whose outer ends are journaled in end bearings 14, 16, the outer races of which are press-fitted into the bore wall of the housing in the usual manner. The relatively inner end of the housing 10 is effectively closed by a tubular adapter 18 and an inner-end seal 20, and the corresponding end of the spindle extends through the adapter for connection to a flexible drive shaft, as is usual. The fixed casing in which the flexible drive shaft runs is of course secured to the housing 10 via said adapter. Since the details of the flexible shaft, its casing, and the connections thereof to spindle 12 and adapter 18 are well known and form no part of the present invention, further description and illustration thereof are deemed unnecessary.

At its outer or tip end, the housing is closed by a solid tip element 22 threaded into said end, said tip element preferably having a hollow inner end into which extends the cap screw 24, which, in conjunction with the stop washer 26 for the frontend bearing 16, serves to fix the relative axial position of spindle within the housing 10.

Thus, when the so-far described head is held immersed in a mass of concrete and placed in operation by imparting high-speed rotation to the eccentrically-weighted spindle 12, said head moves in an orbital path about the geometric center of the head responsive to the centrifugal force applied thereto by the spindle. Consequent to its aforesaid movement, the head transmits energy to the mass of concrete surrounding the same in the form of diametrically paired pressure and suction forces which progress about the full 360 circumference of the circle of the head during the course of each cycle of rotation of the eccentrically-weighted spindle 12, which act to compact and densify the concrete in known manner.

According to the invention, new external configuration is imparted to a basic round-head vibrator as just described through the provision of longitudinal splines fabricated to or formed integrally on the external periphery of the head housing 10 thereof. More particularly, FIG. 2 illustrates four such longitudinal splines designated 30, 32, 34 and 36, which are secured to the external surface of the housing 10 at equidistantly spaced points along the circumference thereof, as by welding, said splines having square section of dimension which corresponds generally to the wall thickness of the housing 10 and length such that they extend throughout the major length of the said head.

Alternatively, rather than being fabricated to an existing round-section housing, as with FIGS. 1 and 2 construction, the splines (also designated 30-36 inclusive) may be formed integral with the housing in a forging or casting operation, with the resulting integrally-splined round housing being illustrated in FIG. 3.

The next following FIGS. 4 and 5 illustrate that the invention is not limited to the new configuration provided by but four external splines on a round-section housing body, but may instead be provided by a greater number of splines, such as six such splines designated 30, 32, 34, 36, 38 and 40 in said figures. Said splines will be equally spaced apart on 60 radial center lines and will be preferably formed integral with the housing 10. FIG. 4 shows that the splines may have straight sides, where-as FIG. 5 shows yet another variant according to which the splines have sloped sides. In general, the choice between the straight-sided and the sloped-sided splines will be determined by factors such as maximum wear life, ease of manufacture, etc., since the action of the splines appears to be the same regardless of whether they have straight or sloped sides, and this applies also to the choice between the welded-on and the cast-on or forged splines.

To illustrate the advantages of the improved externally splined round-head vibrator of the present invention over not only the conventional round-head vibrator, but also the more recent square-head vibrator as well, reference is had to FIGS. 6-9 inclusive which, for analysis purposes, depict the action of each of the head configurations under discussion in a mass of concrete assumed to be a substantial stiff or no-slump concrete. All views further assume the eccentrically-weighted spindles of the heads each to be turning clockwise and to be in angular position which has resulted in the relatively upper portion of the head housing having reached the 12 oclock position during the course of its movement from the 9 oclock to the 3 oclock positions of its orbital movement. It is further explained that, on the above assumption of substantially non-flowing concrete and considering that the vibrator head does not rotate but instead moves much as a pestle held in the hand and moved about the inside of a mortar, the head will tend to push back or evacuate the concrete and eventually make a hole whose boundaries or boundary defines a so-called envelope. Thus, referring to FIG. 6, the hole assumed to be made by the roundhead vibrator will be round and of a diameter exceeding that of the head by twice the radius of eccentricity of the orbital axis of the head to its fixed geometric axis. For analysis purposes, such means that at its extreme 12 oclock position in which it is shown, the round head, after ithas once made the hole in the concrete, contacts the so-called concrete envelope at but one point, i.e. the uppermost or 12 oclock point of its periphery, and such with less a radial force than a tangential force of frictional drag, and this is true for every oclock position that the head takes within its envelope or hole during the course of its making a complete orbit with each 360 rotation of its eccentrically-weighted spindle. Also to be observed is that throughout the arc of the envelope represented by, say, the 1 oclock through the 11 oclock position of the head, the latter is completely out of contact with the envelope. Of course, it is to be understood that with any degree of slump greater than that characterizing the non-flowing concrete, the concrete will move or tend to move into and fill any space developing between head and envelope in respose to the partial vacuum which the head creates when it moves away from the concrete which it has previously contacted, such resulting in the concrete mass being set up to be again struck or pushed outwardly as the head moves radially outwardly in progressing throughout its full orbital path.

Referring now to FIG. 7 depicting the square-head vibrator within its so-called concrete envelope, such shows the uppermost face of the head as having just reached the uppermost or extreme limit of its 12 oclock position. Even though acting on the concrete throughout the full width of said uppermost face, FIG. 7 shows that said face is at best capable of transmitting to the concrete compacted thereby but a straight outward radial force 1. And the stiffer the concrete, the more this force is likely to be in the nature of a slow broadside push rather than what might be termed a sharp, localized punch force. In passing, such action of the square-head vibrator would appear to explain its high power requirements and the resulting early failure of its flexible driving shaft, as compared to the round-head vibrator. Furthermore, since the faces of the orbiting square-head vibrator become effective to transmit energy to the concrete mass surrounding same at intervals which are spaced in time one-quarter cycle apart, and then only along a line which extends radially outwardly from the striking or pushing face, it becomes apparent that While the action of the square-head vibrator is clearly more effective than that of the prior round-head vibrator, it nonetheless leaves much to be desired in the way of maximum effectiveness.

Now considering the action of the splined round-head vibrators of the invention, FIG. 8 illustrates the foursplined round-head vibrator according to the FIGS. 1-3 embodiment operating within the envelope of concrete which it forms when immersed in a no-slump concrete or tends to form when the concrete is more flowable. The principal point to be noted is that, responsively to the head moving to the outermost limit of its 12 oclock position, splines designated A, B and C thereof apply widely spaced incisive forces 1 on the concrete mass engaged by the upper half of the head. That is to say, in addition to the face b of spline B applying an outwardly radial force on the concrete, comparing to that applied or transmitted by the uppermost face of the square-head vibrator according to FIG. 7, face 0 of spline A and face a of spline C each also applies an upward force on the concrete contacted thereby. However, Whereas the force 1 applied by face b of spline B is radially outward, the forces 1 applied by face c of spline A and face a of spline C are relatively horizontal, just as the force f, which will be delivered by face 0 of spline B becomes predominantly horizontal as said spline B begins to move from its 12 oclock to its 3 oclock position.

Analysis of these horizontal vs. radially outward forces 7 shows that they act quite differently from one another. In explanation, the force delivered by face c of spline A acts on the local mass of concrete extending between splines A and B, and this action is to positively move said local :mass of concrete toward the retreating face a of spline B as the latter moves from its 9 oclock to its 12 oclock positions and from thence to its 3 oclock position, and so on. Since this movement of the concrete toward each retreating spline is now a positive, forceful movement and furthermore acts in a direction favorable to filling in any space between concrete and retreating spline, it will be appreciated that this fillingin movement proceeds in positive manner, rather than depending mainly on partial vacuum as heretofore.

Similarly, the force 1 engendered by movement of spline face a of spline C, together with movement of spline face b of spline B to its 12 oclock position, acts on the concrete in the localized mass thereof extending between splines B and C in manner as to move said concrete against the advancing face 0 of spline B, and thereby in effect sets up the concrete for the side punch which the leading face c of spline B will deliver thereto as said spline moves to its 3 oclock position.

In summary, the splines of the splined round-head vibrator shown in FIG. 8 transmit plural forces on the concrete contacted thereby which, in addition to acting in straight radial direction as with the square-head vibrator previously described, also act in direction as to forcefully move localized areas of the concrete disposed between the splines sidewardly against the spline then in its outermost radial position, this motion acting to positively supplement the return movement by vacuum of the concrete into any space formed between the outer surface or surfaces of the head and the surrounding concrete envelope. At this point, it will be observed that the arcuate peripheral portions of the head extending between the splines act on the concrete in the same manner as the corresponding peripheral portions of the round-head vibrator acts thereon, so that the action of the splines is clearly in supplement to that provided by the known round-head vibrator.

The same if not even a more favorable distribution of the forces 1 developed by the splines, as insures a more positive return of the concrete into cont-act with the retreating faces of the splines, is obtained by the sixsplined round-head vibrato-r shown in FIG. 9, wherein the splines are designated A-F inclusive and their effective faces by the letters a, b and 0, generally as in FIG. 8. Thus, with the spline B moving to its extreme twelve oclock position, its face b will have engendered a force 1 acting in radial direction on the concrete, as explained above in connection with the action of face b of spline B of the four-splined round-head vibrator shown in FIG. 8. In addition, face c of spline A and face a of spline C are each shown to be transmitting a force j to the localized masses of concrete between splines A and B, B and C, respectively, which act substantially horizontally rather than radially outward, thereby causing positive horizontal movement of the concrete toward the intermediate spline B. When it is considered that these so-called horizontal forces which each two spaced splines deliver to the concrete intervening between said splines and the then intermediate spline is over and above the straight radial force developed on the concrete as each spline assumes its relatively twelve oclock position, it will be appreciated that the six-splined round-head vibrator, as with the four-splined round-head vibrator shown in FIG. 8, is substantially more elfective than is the square-head vibrator shown in FIG. 7.

Without further analysis, it is believed that the above description of the structure and action of a splined round-head concrete vibrator according to the present invention will suffice to disclose same and explain its operating principle to those skilled in the art. Since the splined round-head vibrator, even though provided with splines as aforesaid, is basically a round-head vibrator, it possesses the long-life and wear resistance properties characterizing the conventional round-head vibrator. Finally, it is believed to be self-evident that, because of the sharp, punch-type character and better distribution of the forces 1 engendered by and transmitted to the concrete by the splines of the splined head vibrator as aforesaid, the power requirements thereof are less than those of the square-head vibrator whose wide faces act broadside on the concrete contacted thereby and, in so doing, perforce expand a great deal of energy.

As many changes could be made in carrying out the above construct-ions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A concrete vibrator of the immersion type comprising an elongated vibrating head of basic round-head construction consisting of a thick-wall elongated shell closed at one end by a tip member which projects axially therefrom, said head being provided with a plurality of longitudinal, circumferentially spaced, rigid splines projecting radially outwardly from the outer peripheral surface of said shell and which extend substantially the full working length thereof but terminate short of said tip member, said splines having substantially square section and the substantially right-angularly related outer and side wall surfaces of the splines and the arcuate outer peripheral portions of the shell which extend between the splines providing the external configuration of the head and combining to form the concrete-working surface thereof, and means extending into the other end of the shell for imparting nonrotary orbital motion to the so externally configured head.

2. A concrete vibrator according to claim 1, wherein the housing is provided with four said splines which are equally spaced from one another about the circumference of the housing.

3. A concrete vibrator according to claim 1, wherein the housing is provided with six said splines which are equally spaced from one another about the circumference of the housing.

4. A concrete vibrator according to claim 1, wherein the splines have straight sides.

5. A concrete vibrator according to claim 1, wherein the splines have sloped sides.

6. A concrete vibrator according to claim 1, wherein the splines are formed separate from the housing and are secured thereto by Welding.

7. A concrete vibrator according to claim 1, wherein the housing and splines are integral one with the other.

References Cited by the Examiner UNITED STATES PATENTS 2,705,618 4/ 1955 Wyzenbeck.

FOREIGN PATENTS 280,774 5/ 1952 Switzerland.

WALTER A. SCHEEL, Primary Examiner.

JAMES S. SHANK, Examiner. 

1. A CONCRETE VIBRATOR OF THE IMMERSION TYPE COMPRISING AN ELONGATED VIBRATING HEAD OF BASIC ROUND-HEAD CONSTRUCTION CONSISTING OF A THICK-WALL ELONGATED SHELL CLOSED AT ONE END BY A TIP MEMBER WHICH PROJECTS AXIALLY THEREFROM, SAID HEAD BEING PROVIDED WITH A PLURALITY OF LONGITUDINAL, CIRCUMFERENTIALLY SPACED, RIGID SPLINES PROJECTING RADIALLY OUTWARDLY FROM THE OUTER PERIPHERAL SURFACE OF THE SAID SHELL AND WHICH EXTEND SUBSTANTIALLY THE FULL WORKING LENGTH THEREOF BUT TERMINATE SHORT OF SAID TIP MEMBER, SAID SPLINES HAVING SUBSTANTIALLY SQUARE SECTION AND THE SUBSTANTIALLY RIGHT-ANGULARLY RELATED OUTER AND SIDE WALL SURFACES OF THE SPLINES AND THE ARCUATE OUTER PERIPHERAL PORTIONS OF THE SHELL WHICH EXTEND BETWEEN THE SPLINES PROVIDING THE EXTERNAL CONFIGURATION OF THE HEAD AND COMBINING TO FORM THE CONCRETE-WORKING SURFACE THEREOF, AND MEANS EXTENDING INTO THE OTHER END OF THE SHELL FOR IMPARTING NONROTARY ORBITAL MOTION TO THE SO EXTERNALLY CONFIGURED HEAD. 